Rare 'Heat Burst' Sees Temperature in One Country Rise By 11 Degrees Fahrenheit in Just 20 Minutes

A natural phenomenon called a "heat burst" happened early this morning in Malta when the temperature rose more than 11 degrees Fahrenheit in 20 minutes.

Andrea Muscat, who runs the Maltese Islands Weather website, told the Times of Malta that the weather change was recorded in parts of Malta, but especially in Gozo, an island northwest of the mainland.

Malta residents reported feeling the heat burst and had to turn on their air conditioning. Residents of Gozo felt the heat the most, as fewer people towards the south of the islands felt the effect.

Gozo residents shared their experiences of being woken up by the heat on Muscat's Maltese Islands Weather page on Facebook, in response to a post that said: "Did you wake up feeling extremely warm just after 02:00? Was the wind howling? You weren't imagining it! Parts of the Maltese Islands experienced a probable heat burst!"

Loretta Dempsey said it was "like a sauna outside on the balcony" and Anita Naudi said the heat burst explained why she "was so hot and had to kick the covers off."

Muscat, who has been recording weather data since 2012 believes that this occurrence is only the fourth time the phenomenon has happened in eight years. He says it normally happens around April or May.

Gozo Malta Heat Burst
A patchwork of of fields and crops on the tiny island of Gozo where every square foot of land is valuable for cultivating fruit and vegetables for Malta. The island felt the effects of a heat burst early on Thursday morning. Tom Stoddart/Getty

The heat burst happened at 2.19 a.m. local time when the air temperature rose from (69 degrees Fahrenheit to 80 degrees Fahrenheit in 20 minutes. Levels of humidity dropped from 80 percent to 37 percent in a few minutes too.

According to Muscat, conditions have to be quite specific for a heat burst to occur: "In typical heat burst fashion, the wind increased dramatically from a complete calm to 40.2 km/h (Force 6).

"The behavior of air pressure also reveals tell-tale signs of a heat burst. It climbed by 2hPa, from 1009.5hPa to 1011.5hPa, which—in layman's terms—means the weight of the air above the ground changed dramatically. A heat burst has been likened to someone blowing down on a puddle of water."

This morning's heat burst could have been caused by a cut-off low-pressure system that traveled across the Mediterranean on Wednesday night and early Thursday morning, and which contained isolated thunderstorms. One thunderstorm passed off Gozo's west coast, which likely caused the heat burst, according to Muscat.

A heat burst is caused when a thunderstorm starts to dissipate and its clouds rise, which leaves a layer of cold air beneath. The moisture in the air has been eliminated by earlier precipitation.

Disappearing updrafts, which are currents of rising air within clouds, and gravity causes dense air to sink to the ground. It accelerates downward and the air faces increasing pressure and friction.

Atmospheric pressure causes the air to warm under compression, plus the friction between falling and stationary air particles creates heat too. A heated, dry pocket of air hits the surface and forces a warm gusty wind to disperse from the point of impact.